In this paper, three accident scenario analysis techniques are presented and compared regarding their efficiency vs. the demanded resources. The complexity of modern industrial systems has prompted the development of accident analysis techniques that should thoroughly investigate accidents. The idea of criteria classification to fulfill this requirement has been proposed by other researchers and is examined here too. The comparison is done through the application of Event Tree analysis, Fault Tree analysis and Petri Nets technique-two relatively simple and a more demanding methodology-on the same hazardous chemical facility in view of analyzing an accident scenario of a hazardous transfer procedure. Accident scenario analysis techniques are essential not only in learning lessons from unfortunate events in the chemical industry but also in preventing the occurrence of such events in the future and in communicating risk more efficiently. (C) 2004 Elsevier Ltd. All rights reserved.